There are many cases, in which two rotary members are connected by a coupling device having a function of absorbing axis deviation. For example, the coupling device is used in a brake fluid pressure control apparatus for a vehicle having control functions such as ABS (Antilock Brake System for antilock control), ESC (Electronic Stability Control for sideslip suppression control), TCS (Traction Control System) and the like, and the apparatus includes a pump that is driven by a motor.
The pump includes a plunger pump and a gear pump. In the gear pump, an output shaft of a motor is connected to a rotor shaft having a pump rotor mounted thereto, and the motor drives to rotate the rotor shaft.
The connection between the rotor shaft and the output shaft of the motor is made by using a coupling device capable of absorbing axis deviation because the axis deviation inevitably occurs between both the shafts. The coupling device is disclosed in JP-A-2004-68836 and JP-A-2011-80530, for example.